Pigmented Spindle Cell Nevus (Reed Nevus)

 Typically show hyperchromatic-staining nuclei with small nucleoli


image Cytoplasm with prominent melanin pigmentation


• Atypical Reed nevus
image Often larger, more cellular lesions

image Increased mitotic activity, especially in junctional component




Top Differential Diagnoses




• Spitz nevus
image More common in children, on head and neck and trunk region (Reed nevi more often on extremities)

image Composed of mixture of spindled and epithelioid-shaped melanocytes (more spindled cells in Reed nevi)

• Melanoma
image More often occurs in older patients in sun-damaged skin

image Greater cytologic atypia and pleomorphism

image Dermal mitoses and lack of maturation with descent

image
Clinical Photograph of Reed Nevus
Clinical photograph shows a pigmented spindle cell nevus on the knee of a young adult patient. This case shows dark pigmentation, except 1 area at the top of the lesion with depigmentation image. (Courtesy P. Hsu, MD.)


image
Reed Nevus at Low Magnification
Histologic examination of a Reed nevus shows fusion of rete ridges by a proliferation of junctional pigmented spindle cells, which show a characteristic streaming together image pattern.

image
Reed Nevus With Junctional Nests Showing Bridging
Higher magnification shows bridging across rete ridges by junctional nests image of streaming pigmented spindle-shaped cells. The cells show hyperchromatic nuclei and heavily pigmented cytoplasm. Note the numerous darkly pigmented melanophages in the superficial dermis image.

image
Reed Nevus at High Magnification
High magnification of the intraepidermal component shows elongated spindle-shaped cells with pigmented cytoplasmic processes image.


TERMINOLOGY


Abbreviations




• Pigmented spindle cell nevus (PSCN)


Synonyms




• Pigmented spindle cell nevus of Reed


Definitions




• Melanocytic proliferation, usually predominantly junctional, and composed of spindle-shaped cells with heavy cytoplasmic pigmentation

• Often considered variant of Spitz nevus, which occurs more frequently in adults


ETIOLOGY/PATHOGENESIS



Unknown




• May be related to solar exposure in some cases


CLINICAL ISSUES


Epidemiology




• Incidence
image Relatively uncommon tumors

• Age
image Typically young adults (< 40 years old)

• Sex
image More common in females

• Ethnicity
image Caucasian patients in most cases


Site




• Most often presents on extremities, especially leg
image Classic presentation is on thigh of young woman


Presentation




• Pigmented lesion
image Usually papular but can be nodular


Treatment




• Surgical approaches
image Complete excision is curative

– Typically recommended in partially sampled lesions

– To allow for complete evaluation to exclude more atypical areas

– Also to prevent recurrence

Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Pigmented Spindle Cell Nevus (Reed Nevus)
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